[Domain Mapping] Domain Mapping - Can't install

When I go to https://premium.wpmudev.org/project/domain-mapping/ to install the domain mapping plugin, I click on the [Install] button and get a dialog box that says:
"Which website would you like to install Domain Mapping on?"

It is prefilled with my network domain with "REQUIRES MULTISITE" to the right of it.
Below that it says:
"To install Domain Mapping on a new website, first download and install the WPMU DEV Dashboard to sync up your website."
I have the dashboard installed, and I can't get past this to get on with trying to install the plugin.